Heater for electrolytic incandescent lamps.



UNITED STATES PATENT OFFICE.

JAMES SWINBURNE, OF WVESTMINSTER, ENGLAND, ASSIGNOR TO,THE ELECTRICRESISTANCE & HEATING COMPANY, LIMITED, OF LONDON,

. ENGLAND.

HEATER FOR ELECTROLYTIC INCANDESCENT LAMPS.

SPECIFICATION forming part of Letters Patent No; 681,352, dated August27, 1901.

Application filed January 8, 1901. Serial No. 42,562. (No model.)

To all whom it may concern.-

Be it known that I, JAMES SWINBURNE, a citizen of England, residing at82 Victoria street, Westminster, in the county of London, England, haveinvented certain new and useful Improvements in Heaters for ElectrolyticIncandescent Lamps, (for which I have applied for a patent in GreatBritain, dated June 16, 1900, No. 10,940,) of which the following is aspecification.

My invention has reference to heaters for electrolytic incandescentelectric lamps.

Resistance-heaters can be made of carbon or metal or other conductormixed with clay; but when the conducting material oxidizes in the air atthe temperature necessary for a heater the resistance is greatly alteredand can no longer be used as a heater. To overcome this difficulty, Iprotect the oxidizable conducting material against the action of the airby vitrifying the insulating material or by glazing it.

A resistance-heater according to my invention may be made as follows:Graphite is kneaded up with kaolin and squirted into the form of thinrods or spirals. These are dried and baked at such a high temperaturethat the kaolin is Vitrified. To facilitate this vitrification, thekaolin may have feldspar added to it, or the clay used for making chinamay be e loyed instead of kaolin and feldspar.

In s l ad of vitrifying the resistance it may be glazed by dipping itafter it has been fired into water having glaze suspended in it and thenfiring it in the usual way. Glazes which are soluble in Water, such asboracic acid, may be employed.

Oarbids, silicides, silicon, or finely-powdered metal, such as tungsten,(preferably prepared by electrolyzing a fused tungstate,) may beemployed as the conducting material instead of carbon.

Having thus described the nature of this invention and the best means Iknow of carrying the same into practical efiect, I claim- Aresistance-heater for an electrolytic incandescent lamp consisting of aconducting material such as carbon mixed with non-con ducting materialsuch as kaolin formed into the desired shape and vitrified or glazedsubstantially as and for the purpose set forth.

In testimony whereof I have hereunto set my hand in presence of twosubscribing wit- IIGSSGS.

JAMES SWINBURNE. \Vitnesses:

Gno. H. RIDGWAY, A. MAYFIELD IRELAND.

